Various precipitation techniques have been proposed for obtaining a particulate polymeric material from a polymer solution. For instance, commonly a non-solvent is added to a polymer solution while undergoing agitation until the polymer is no longer dissolved. Alternatively, the polymer solution may be added to a non-solvent while undergoing agitation to precipitate the polymer. Commonly such prior art polymer precipitation techniques have yielded a particulate material of relatively low surface area, i.e. particles having a surface area below about 5 square meters per gram.
There accordingly has remained a need for a simple procedure capable of increasing the surface area when the polymeric material is intended for specialized industrial applications wherein such parameter is of importance. While milling and grinding of the previously precipitated particles advantageously will reduce the particle size to some degree and possibly increase the surface area, such additional processing often is highly time consuming and even then may be incapable of yielding the desired extremely small particles, particularly if the polymeric material involved is a high temperature resistant intractable polymer of the BBB type.
U.S. Ser. No. 424,996, filed Dec. 14, 1973, discloses one approach wherein a BBB type polymer is formed under polymerization conditions wherein polymer particles of unusually high surface area inherently are formed.
It is an object of the present invention to provide an improved process for yielding a particulate polymeric material having an unusually high surface area.
It is an object of the invention to provide an improved process wherein a dissolved preformed polymeric material readily may be transformed to a particulate polymeric material of unusually high surface area, i.e. at least 125 square meters per gram.
It is another object of the invention to provide an improved process wherein dissolved preformed BBB type polymer readily may be transformed to a particulate polymeric material of unusually high surface area.
These and other objects, as well as the scope, nature, and utilization of the present invention will be apparent from the following detailed description and appended claims.